The book is written so that both experienced and novice Tclers can find useful information inside. It starts with quick introduction to Tcl and its networking support for those who are less familiar with them. Authors focus on showing practical, yet simple examples for each module and command described so that reader understands how to use them when solving the real life problems. The examples given are useful programs that try to solve real-world needs. All sample programs are clear and concise yet nothing essential is left out and the programming style focuses on readability rather than on stylistic rigor or efficiency. This book is for Tcl developers with basic network programming concepts, who want to add networking capabilities to their applications. Working knowledge of Tcl and basic experience of network protocols will be useful. The reader should be familiar with basic concepts used in modern networking - keywords like TCP, HTTP or XML should not be a mystery. The book does not require advanced knowledge of Tcl - the first chapters will swiftly introduce the reader into it, allowing refreshing the information or gaining a quick overview of the Tcl language abilities.